Guide wire with hydrophilically coated tip

ABSTRACT

A guide wire including a lubricous distal portion and a less lubricous intermediate portion proximal of said distal portion. One guide wire provides a highly lubricous distal portion with a hydrophilic layer and a less lubricous intermediate portion with a hydrophobic layer. Another guide wire provides a lubricous distal portion with a polymer tip that is itself hydrophilic. Yet another guide wire provides a less lubricous intermediate portion using a stainless steel coil helically wound around the tapering intermediate portion. The coil is preferably coated with a hydrophobic coating such as PTFE or silicone. The coil can either abut the distal portion proximal end or extend into the distal portion interior.

FIELD OF THE INVENTION

The present invention relates generally to intravascular guide wires. Inparticular, the present invention relates to guide wires having alubricous hydrophilic tip and a less lubricous intermediate portionproximal the distal tip.

BACKGROUND OF THE INVENTION

Guide wires are used in various procedures within various conduits inthe body. In particular, they are used in Percutaneous TransluminalCoronary Angioplasty (PCTA) and other coronary procedures. This caninvolve inserting a guide wire through an incision in the femoral arterynear the groin, advancing the guide wire over the aortic arch, into acoronary artery, and across a lesion to be treated. Guide wires can beinserted directly into the vasculature or within a guide catheter. Thedistal end of the guide wire ultimately lies directly within thevasculature.

Guide wires serve to guide devices into position for both therapeuticand diagnostic purposes. For this to happen, the guide wire itself mustbe properly positioned. This is difficult, as it involves moving a wiretip through a narrow opening within a narrow vessel, from 180centimeters away. This task can be especially difficult as the guidewire must be extremely flexible at the distal end to enable the guidewire tip to enter vessel branches at various angles. The extremeflexibility can come at the expense of axial or rotational strength.Improved responsiveness to remotely applied forces, both rotational andaxial, has been provided by reducing friction along the guide wirelength. In particular, providing a highly lubricous guide wire distalregion of about 12 inches has proven advantageous in maneuvering guidewires through the arteries to reach the site of blockage. Having thissame lubricous coating on the tip of the wire has been advantageous inmaking the wire perform better in finding small openings in theblockages and crossing them.

Once the guide wire tip is in position, devices including catheters areadvanced into position over the guide wire and withdrawn over the guidewire. Such catheter movement acts upon, and tends to move, the guidewire contained within. This can tend to dislodge the guide wire tip.Minor patient movement including breathing also acts to move the guidewire as does handling of the guide wire proximal portion extending fromthe patient. Dislodging the guide wire tip may require repositioning theguide wire, with the attendant time and effort. Once in position,therefore, stability and resistance to applied forces is preferred overthe initially desirable ease of movement and responsiveness to appliedforces.

What is desirable and has not been provided is a guide wire easilymaneuvered into position across a tight lesion, yet providing stabilityand resistance to movement once the guide wire is in position.

SUMMARY OF THE INVENTION

The present invention provides a guide wire having a highly lubricousdistal portion, followed proximally by a less lubricous intermediateportion, followed proximally by a proximal portion. The guide wireincludes a core member within, preferably formed of metal and having aproximal constant cross section portion, followed distally by a taperedportion, followed distally by a reduced cross section portion. Thetapered portion can have multiple tapers. The distal end of the reducedcross section portion is preferably flattened into a ribbon, providinggreater flexure in one plane. A preferred core has a circular crosssection in the proximal and tapered portions. One guide wire embodimenthas a intermediate and distal portion length totalling about 12 to 14inches. A preferred length for the distal portion is about 1 to 3centimeters.

A preferred guide wire achieves a lubricous distal portion by having ahydrophilic surface in the distal portion. A less lubricous intermediateportion is achieved by having a hydrophobic surface in the intermediateportion. The hydrophilic surface has a very low coefficient of frictionwhen placed against an artery wall in a blood filled artery. Thehydrophobic surface has a higher coefficient of friction against theartery wall.

The present invention distal portion can be formed of a polymer notnecessarily hydrophilic, but having a hydrophilic coating thereover. Theintermediate portion can be formed of a hydrophobic polymer sleeve overthe core wire or a polymer sleeve over the core wire having ahydrophobic coating. In another embodiment, the intermediate portion caninclude a coil around the core wire, the coil preferably having ahydrophobic coating. The coil wire abuts the distal portion in oneembodiment, and is embedded beneath the distal polymer in anotherembodiment. In yet another embodiment, the distal portion includes adistal tip having a proximally tapered proximal portion, and the coilwire distal end contacts the distal tip in the tapered portion, therebycentering the coil.

The present invention provides the ability to cross tight lesions byhaving a highly lubricous, low friction, distal portion, which isrelatively easy to slide through a narrowed vessel region. The extremelylubricous portion is limited to a shorter length relative to previousdevices. A preferred length is about 1 inch. The lubricity is limited tothe portion where the extreme lubricity is most needed, the distalportion. Lower friction is required in the extreme distal portionbecause the core member there is narrower and therefore weaker, nothaving the strength of the more proximal portion to handle being axiallypushed from the proximal end against obstructions. Low friction is alsorequired in this portion because this is the portion that is required toinitially cross an extremely tight lesion, something not required of themore proximal portion. The low friction facilitates the wire tip firstpiloting into the small remaining opening in the lesion and thencrossing the lesion without buckling the wire.

To counteract the highly lubricous, low friction distal portion, thepresent invention deliberately provides a less lubricous, higherfriction intermediate portion, proximal of the distal portion. Theintermediate portion can lie against an artery wall, or guide catheterwall, "anchoring" the guide wire. The present invention, by having ananchoring portion proximal of the distal portion, provides resistance toforces such as catheter movement over the guide wire, which could act todislodge the guide wire tip from its desired position.

While the anchoring portion friction will not prevent all movement ofthe guide wire, it provides sufficient static friction to resistunintentional movement due to either catheter movement or patientmovement. In this way, a series of minor forces acting on the guide wireproximal portion, if below the threshold of static friction presented bythe anchoring portion, will not be translated into a series of minormovements of the guide wire distal tip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, side cross-sectional view of a guide wire, inaccordance with the present invention, having a coil in the intermediateportion;

FIG. 2 is a fragmentary, side cross-sectional view of a secondembodiment of a guide wire having a core wire shown in phantom;

FIG. 3 is a fragmentary, side cross-sectional view of a third embodimentof a guide wire having a coil extending into the distal tip;

FIG. 4 is a fragmentary, side cross-sectional view of a fourthembodiment of a guide wire having a two part coil extending into thedistal tip; and

FIG. 5 is a fragmentary side cross-sectional view of a fifth embodimentof a guide wire having a proximally tapered polymer tip and a coilsitting on the taper.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a fragmentary, side cross-sectional view of a guidewire 20 having a distal portion 22, an intermediate portion 24, and aproximal portion 26. Guide wire 20 has a surface extending the lengththereof, as indicated at 21. The length of distal portion 22 isindicated by arrows 40 and the length of intermediate portion 24 byarrows 44. Guide wire 20 includes an elongate core member 28 having aconstant cross section portion 30, a tapered portion 32 and a reducedcross section portion 34. Core member 28 preferably has a circular crosssection in portions 30 and 32. The intermediate tapered portion 32 maycomprise a single taper or a series of tapers with regions of constantdiameter in between. Core 28 is preferably formed from high tensilestrength stainless steel wire or a super-elastic alloy such as Nitinol.

Core reduced cross section portion 34, illustrated lying within a distalportion 22, provides extreme flexibility to the guide wire where needed,at the extreme distal end. Reduced cross section portion 34 ispreferably flatter in one dimension than another, forming a ribbon,providing more flexibility in one dimension than another. Tipflexibility is desirable for insinuating the guide wire into ever moredistal and tortuous coronary arteries. The embodiment of distal portion22 illustrated can include a distal tip 38 encasing core reduced crosssection portion 34. In a preferred embodiment, distal tip 38 includes apolymeric material. Distal tip 38 is preferably radiopaque to allow fortracking the tip position using fluoroscopy. In one embodiment, tip 38includes polyurethane and is loaded with tungsten, 85 to 90 percent byweight, for radiopacity. In one embodiment, a polyurethane sleeve formsdistal tip 38, which can be between about 1/2 and 7 centimeters inlength. In a preferred embodiment, tip 38 is between 1 and 3 centimetersin length.

Distal portion 22 according to the present invention is lubricous. In apreferred embodiment, distal portion 22 is extremely lubricous. In oneembodiment, the lubricity is provided by having a hydrophilic materialat the surface of distal portion 22. A hydrophilic surface makes thesurface highly lubricous when in contact with a water based fluid suchas blood. In the embodiment illustrated in FIG. 1, lubricity is providedby a distal layer 36 over reduced diameter portion 34 and distal tip 38.A hydrophilic coating over the guide wire presents very little frictionwhen sliding through the artery interior. This provides ease of crossingtight lesions, allowing difficult and distally remote lesions to betreated. In one embodiment, distal layer 38 includes apolyvinylpyrrolidone (PVP) coating. In another embodiment, distal layer38 includes a polyethyl maleic anhydride coating. In a preferredembodiment, distal portion 22 is about 0.014 inches in diameter.

Proximal of distal portion 22 is intermediate portion 24 which has alubricity less than that of distal portion 22. In a preferredembodiment, intermediate portion 24 has length 44 of about 20 to about30 centimeters. In one embodiment, intermediate portion 24 is about 28centimeters long and about 0.0130 to 0.0135 inches in diameter. Guidewires used to deliver stiffer devices may have a shorter intermediateregion to make the wire more supportive. In these cases intermediateportion 24 may be as short as 3 centimeters. In the embodiment depictedin FIG. 1, intermediate portion 24 includes tapered core portion 32which is encased in a coil 42. A preferred coil is formed of stainlesssteel and coated with hydrophobic coating. A preferred hydrophobiccoating is PTFE or silicone. Coil 42, by presenting a series of wiresoriented transversely to the axial direction of guide wire movement,provides resistance to axial movement. The coil also provides increasedpushability and kink resistance for tapered core portion 32. Incompression, the coil provides axial strength over the length of taperedcore portion 32 which decreases in strength with decreasing core crosssection. The distal end of coil 42 can be attached to core 28 usingsolder or adhesive. The proximal end of coil 28 is preferably secured tocore 28 by adhesive.

Intermediate portion 24 provides a higher friction anchoring portion tomaintain the position of distal portion 22. If too much of the guidewire is extremely lubricous, the distal tip can be difficult to fixexactly in position, as catheter advancement and retraction over theguide wire can apply forces to the guide wire, tending to move the guidewire tip. Patient movement, including breathing, can also translate intomovement at the guide wire distal tip. By providing an intermediateregion having a less lubricous surface, an intermediate anchoring regionis provided, which presents friction against the vessel wall, presentingresistance to forces that would otherwise be translated into movement atthe distal tip. While the intermediate anchoring portion cannot resistall forces applied to the guide wire and prevent all tip movement, thestatic friction of the anchored guide wire intermediate portion doesprovide a threshold barrier to lower level forces. Thus, a series ofsmall forces is not necessarily translated into a series of low levelmovements of the guide wire tip.

Proximal portion 26 in a preferred embodiment, extends to the guide wireproximal end. Included in proximal portion in FIG. 1 is constant crosssection core portion 30. In a preferred embodiment, proximal portion 26includes a stainless steel wire about 0.013 inches in diameter and has apolytetrafluoroethylene (PTFE) coating. In one embodiment, proximalportion 26 is less lubricous than intermediate portion 24. In anotherembodiment, proximal portion 26 is more lubricous than intermediateportion 24 but less lubricous than distal portion 22.

FIG. 2 illustrates another embodiment of the invention, guide wire 120,having a proximal portion 126, an intermediate portion 124, and a distalportion 122. Distal portion 122 is preferably about 1/2 to 7 centimetersin length, and intermediate portion 124 can be 1 to 15 inches in lengthand is preferably about 8 to 12 inches in length. Within guide wire 120is a core 128 having a constant diameter portion 130, a tapered portion132 and a reduced diameter portion 134. Core 128 can be substantiallysimilar to core 28 discussed with respect to FIG. 1. Guide wire 120 hasa lubricous distal portion 122 and a less lubricous intermediate portion124. In the embodiment depicted in FIG. 2, distal portion 122 includes adistal tip 136. Distal tip 136 can be similar to distal tip 36 inFIG. 1. In some embodiments, distal tip 136 is formed of polyurethane,and coated with hydrophilic coatings as discussed above with respect toFIG. 1. Distal tip 136 is preferably radiopaque to allow for trackingthe tip position using fluoroscopy. In one embodiment, tip 136 includespolyurethane and is loaded with tungsten, 85 to 90 percent by weight,for radiopacity. Distal tip 136 is preferably more radiopaque thanintermediate portion 124.

Intermediate portion 124 provides a less lubricous portion proximal tolubricous distal portion 122, as in the embodiment of FIG. 1, butwithout requiring a coil. The lower lubricity is provided by having ahydrophobic surface. This can be provided with both hydrophobic sleevesand hydrophobic coatings over sleeves that are not necessarilyhydrophobic. Sleeve 142, illustrated encasing tapered core portion 132,can be formed of a hydrophobic polymer. Hydrophobic polymers includefluorinatedethylenepropylene (FEP) and polytetrafluoroethylene (PTFE).Intermediate portion 124 can also be formed of a material such aspolyether block amide (PEBAX) or polyethylene coated with a lowfriction, hydrophobic coating such as silicone, paralene, PTFE, or FEP.Guide wire 120 can be formed by sleeving tube 142 over core 128, bondingthe tube in place at its proximal end with adhesive, shrinking asuitable distal tip material over reduced diameter core portion 134, andbonding the distal portion of sleeve 142 to the proximal portion of thedistal tip. Another suitable method includes heat shrinking a polymerictube over core 128, grinding the tube to an approximate diameter ofabout 0.0130 to 0.0135 inches, then selectively coating intermediateportion 124 and possibly distal portion 122 also, with one of thehydrophobic coatings, and then coating distal portion 122 with one ofthe previously described hydrophilic coatings.

FIG. 3 illustrates yet another embodiment of the invention, a guide wire220, having proximal portion 226 followed distally by intermediateportion 224 followed distally by distal portion 222. A core 228 proceedsdistally from a constant diameter portion 230 to a tapered portion 232to a reduced diameter portion 234. Intermediate portion 224 includes acoil 242 surrounding the tapered portion of the core, with coil 242proceeding distally from a constant diameter portion 241 to a taperedportion 243 to a reduced diameter portion 244. Core 228 is preferablyflattened into a ribbon shape in reduced diameter portion 244. Reduceddiameter portion 244 is embedded within distal tip 238 when the polymertip is shrunk onto the wire. In this embodiment, neither solder noradhesive are required to secure the distal end of coil 242 to core 228.The proximal end of coil 242 can be secured to core 228 by soldering.Distal tip 238 can be coated with a hydrophilic layer 236 as discussedabove with respect to the embodiment of FIG. 1. The materials of distaltip 238 and layer 236 can be similar to those of distal tip 38 and layer36.

FIG. 4 illustrates yet another embodiment of the invention, a guide wire320, having a proximal portion 326, followed by an intermediate portion324, followed distally by a distal portion 322. A core 328 proceedsdistally from a constant diameter portion 330 to a tapered portion 332,to a reduced diameter portion 334. A coil 342 surrounds core 328 overthe intermediate and distal portions. In the embodiment shown, coil 342is formed of a proximal coil 323 and a distal coil 325 soldered togetherat 340. Proximal coil 323 is preferably formed from a less radiopaquematerial such as stainless steel. This coil can be coated with ahydrophobic coating such as PTFE. Distal coil 325 is preferably formedof a more radiopaque material such as platinum. Combined coil 342 isattached to core 328 proximally with solder at 341 and distally witheither solder or welding at 338. A hydrophilic coating 336 is applied tothe distal portion of distal coil 325 in one embodiment by firstapplying a Tie layer polymer such as polyurethane by dip or spraycoating, followed by applying a hydrophilic coating over the Tie layercoating. The hydrophilic coating can be one of the coatings describedpreviously with respect to guide wire 20 in FIG. 1.

FIG. 5 illustrates yet another embodiment of the invention, a guide wire420 having a proximal portion 426, followed by an intermediate portion424, followed distally by a distal portion 422. A core 428 proceedsdistally from a contact diameter portion 430 to a tapered portion 432,to a reduced diameter portion 434. A distal tip 436, preferably formedof a polymeric substance, surrounds core reduced diameter distal portion434. Distal tip 436 includes a tapered portion 437, which tapersproximally toward core tapered portion 432. Guide wire 420 includes acoil 442 which extends distally over core tapered portion 432. Coil 442has a distal end 443 which contacts and terminates within distal tiptapered portion 437. Coil 442 is thus always centered on core 428, astransverse movement of coil distal end 443 is opposed by distal tiptapered portion 437. Tip 436 can be heated to embed end 443 therein.

While use of the present invention can be described with reference toany of the embodiments, the embodiment of FIG. 1 is selected for furtherillustration. In use, core reduced diameter portion 34 can be bent bythe treating physician, prior to insertion into the patient. Having abent distal tip allows orienting the tip for insertion into arteries byrotating the proximal end of the guide wire, which rotates the bentdistal tip toward arterial side branches. The guide wire can be advancedthrough a guide catheter or directly through the vasculature. Afterhaving advanced the guide wire into a coronary artery such as the leftcoronary artery, the guide wire is maneuvered into selected smallerarteries. In attempting to insinuate the distal most portion of theguide wire into smaller arteries, the lubricous tip provides easierinitial advancement into the artery. When a lesion is to be crossed,lubricous distal portion 22 provides low resistance to axial movementinto and through a narrow passage. Low resistance is advantageous asthere is less tendency for core reduced diameter portion 34 to kink orbuckle when pushed by the treating physician from the extreme proximalend.

Once distal portion 22 is across the lesion, it is highly preferred thatthe guide wire tip position not change, despite minor changes inproximal handling of the guide wire, movement of other devices over theguide wire, patient breathing, blood flow, and minor changes infrictional conditions along the guide wire length. The present inventionallows a guide wire to resist these forces by having intermediateportion 24 lie against and be "anchored" to the vessel or guide catheterwall, presenting a higher quantity of static friction that must beovercome to dislodge the guide wire distal tip, than presented withwires having longer lubricous distal surfaces. The present inventionthus makes it less likely that the guide wire will move inside theartery unless the physician is directly intending to move it.

The combination of lubricous distal portion and less lubricousintermediate portion thus serves to promote ease of distal tipadvancement across tight lesions while stabilizing the distal tipposition once placed, allowing other devices to be accurately guidedinto position by the guide wire.

Numerous advantages of the invention covered by this document have beenset forth in the foregoing description. It will be understood, however,that this disclosure is, in many respects, only illustrative. Changesmay be made in details, particularly in matters of shape, size, andarrangement of parts without exceeding the scope of the invention. Theinventions's scope is, of course, defined in the language in which theappended claims are expressed.

What is claimed is:
 1. A guide wire having a distal end and a proximalend comprising:an elongate core; a lubricous distal portion having alength of about 0.5 to 7 centimeters; an intermediate portion, proximalof said distal portion, said intermediate portion being less lubricousthan said distal portion, and said intermediate portion having a lengthof at least about 1 to 15 inches; and a proximal portion proximal ofsaid intermediate portion.
 2. A guide wire as recited in claim 1,whereinsaid guide wire includes a surface, said distal portion surfaceis hydrophilic, and said intermediate portion surface is hydrophobic. 3.A guide wire as recited in claim 2, whereinsaid distal portion surfaceincludes a hydrophilic coating.
 4. A guide wire as recited in claim 2,whereinsaid distal portion surface includes a hydrophilic coating, andsaid intermediate portion surface includes a hydrophobic coating.
 5. Aguide wire as recited in claim 4, wherein said proximal portion includesa lubricous coating over said elongate core.
 6. A guide wire as recitedin claim 5, wherein said proximal lubricous coating ispolytetrafluoroethylene.
 7. A guide wire as recited in claim 1,whereinsaid guide wire includes a surface, said distal portion surfaceis hydrophilic, and said intermediate portion includes a coil aroundsaid elongate core.
 8. A guide wire as recited in claim 7, said distalportion including a polymeric distal tip having a proximally taperedproximal portion, said coil having a distal end, wherein said coildistal end contacts said distal tip within said tapered portion.
 9. Aguide wire as recited in claim 7, whereinsaid intermediate portion coilincludes a hydrophobic coating.
 10. A guide wire as recited in claim 9,whereinsaid elongate core is tapered distally within said intermediateportion.
 11. A guide wire as recited in claim 10, wherein said coilcomprises stainless steel having a silicone coating.
 12. A guide wire asrecited in claim 10, wherein said coil comprises stainless steel havinga polytetrafluoroethylene coating.
 13. A guide wire as recited in claim10, wherein said coil includes a distal tapered portion, said coiltapered portion extending within said guide wire distal portion.